Formation flying, sometimes referred to as station keeping, wherein multiple aircraft are flown in close proximity, may be desired for a multitude of reasons including force multiplication, collaboration or fusion of disparate sensor data, radar signature minimization, reduction in the amount of time required to traverse an area with a fleet of aircraft, etc. Such flight in close proximity to other aircraft increases the risk of aircraft interfering with the flight of another or, in worst case, a midair collision. Establishing and maintaining the desired separation between such aircraft may be done visually in good weather by highly skilled pilots. In poor weather, or in the case of unmanned aircraft, ensuring desired separation requires an alternate means for determining relative position and velocity between participating aircraft. In the past, this has been done using complex systems of equipment and specially trained pilots. These systems tend to be very expensive to develop and maintain, requiring significant amounts of training to use, which causes high workloads for pilots. The systems also emit large amounts of radio frequency energy making them easy to detect and attack, and rely on subsystems such as Global Positioning Systems (GPS) which are easily jammed or otherwise denied. Additionally, the precision of navigation information available from these systems is significantly less than desired for unmanned aerial vehicle swarming operations where the desired separation between aircraft must be minimized.